1. Technical Field of the Invention
This invention relates to a battery unit for vehicles having a plurality of batteries connected electrically by connecting members.
2. Description of the Related Art
In recent years, the lithium batteries and the nickel batteries that have high output and high-energy capacity have been put to practical use as a power supply for driving an automobile. These batteries are provided with electrodes, terminals, and battery containers. A plurality of batteries are grouped together and used as a battery unit.
When the battery unit is used for driving the automobile, intense electric charge/electric discharge will be repeated. Therefore, temperature may be raised by the heat generation of the electrodes accompanying a chemical reaction, and there will be a chance that the performances of the batteries may be deteriorated.
Conventionally, there is disposed in Japanese Patent Application Laid-Open Publication No. 2005-71674, for example, a battery unit for vehicles that can suppress such a heat rise. FIG. 12 shows an upper surface of a conventional battery unit for vehicles, and FIG. 13 shows the upper surface of the conventional battery unit for vehicles with insulating members being provided thereto.
As shown in FIG. 12, a battery unit A for vehicles comprises a plurality of batteries B and a plurality of bus bars C. Pairs of terminal members are projected from the upper surface of each battery B. A plurality of batteries B is laminated in the direction of its thickness to form the battery unit A. The terminal members of the batteries B adjoining in the lamination direction are connected in series with the bus bars C with which the cooling fins are formed.
The heat generated with the electrodes radiates the heat to a heat carrier such as a refrigerant via the terminal members and the bus bar C, by having the refrigerant flow in the lamination direction along the upper surface of the batteries B. Thereby, the rise in heat of the battery unit for vehicles A can be suppressed.
In the battery unit A mentioned above, however, the rise of the heat is suppressed by radiating the generated heat into the refrigerant. There is a possibility that the bus bars C may be short circuited when the bus bars C dew with the humidity contained in the refrigerant, or when a foreign substance is mixed into the refrigerant.
Therefore, insulations arranged between the bus bars C of the adjoining batteries B in the lamination direction are necessary to be secured especially. However, in order to secure the insulations between the bus bars C, insulating members D must be arranged extending in the direction perpendicular to the flow of the refrigerant, as shown in FIG. 13.
Thus, there was a problem that a cooling capability would fall due to the flow of the refrigerant being barred.